- At time t = 0, a small ball is projected vertically upwards from a point A which is 24.5 m above the ground. The ball first comes to instantaneous rest at the point B, where AB = 19.6 m and first hits the ground at time t = T seconds. = The ball is modelled as a particle moving freely under gravity. (a) Find the value of T.

5 sec

Explanation:

t1 is time moving upwards and t2 is time moving downwards.

For v=0 when the ball is highest

s= -1/2(-g)(t1)^2

where s=AB=19.6m and g=9.8m/s^2

Solving t1=2 sec

The height at t1 is 44.1m

and the ball would move through gravity with zero initial velocity.

s= 1/2g(t2)^2

where s=44.1m

Solving t2=3sec

Total time consumed is T= t1+t2= 5sec

molecules are free to separate from each other and will take on the shape of the container. molecules move completely at random and high speeds. they vibrate in a fixed position and do not move around much. molecules expand to the edge of their container.